Just to add my two cents... if they are not native to your local or if the subspecies of gopher you have is not (local specific) you would be breaking a federal law to release them.... Gopher snakes are a generally small and would take years to get to a size where they would help your gopher problem! A rat snake would do better.

Dodo... a snake will survive IF it is in the area where it is native even if having been CBB for generations. The survival skills never go away in reptiles! They know how to hunt.